Process for protecting a substrate with an arylsulfonamidothiadiazole or oxadiazole intumescent agent

ABSTRACT

Intumescent compositions of the invention comprise certain arylsulfonamidothiadiazoles and oxadiazoles, such as 2sulfanilamido-1,3,4-thiadiazole, 3-sulfanilamido-1,2,4-oxadiazole and derivatives thereof. The intumescent agents may be employed in conjunction with additives conventionally used in intumescent compositions. For use in protecting substrates from heat and fire, the intumescent compositions may be applied to the substrates in any suitable manner, such as by electrodeposition, spraying onto an adhesive substrate, or application of a coating composition comprising the intumescent agent.

i M RR 39772207 1 v Qfii E3 1 Umted States 1] 3,772,074

Roth Nov. 13 1973 1 PROCESS FOR PROTECTING A SUBSTRATE WITH AN Primary Examiner-William D. Martin ARYLSULFONAMIDOTHIADIAZOLE ()R Assistant Examiner--Harry J. Gwinnell OXADIAZOLE INTUMESCENT AGENT Ammey-l Rlchard Geama" [75] Inventor: Shirley H. Roth, Highland Park, NJ. [73] Assignee: gitips Service Company, New York, [57] ABSTRACT [22] Filed. i V i lntumescent compositions of the invention comprise certain arylsulfonamidothiadiazoles and oxadiazoles, [21] Appl. No.: 228,381 such as 2-sulfanilamido-l,3,4-thiadiazole, 3-

sulfanilamido1,2,4-oxadiazole and derivatives thereof. The intumescent agents may be employed in [52] US. Cl. 117/136, 106/15 FP 51 Int. Cl. C09d 5/18, C09k 3/28 used [58] Field of Search 117/136 106,15 FF mescent compositions. For use in protecting substrates 252/8 from heat and fire, the intumescent compositions may be applied to the substrates in any suitable manner, [56] References Cited such as by electrodeposition, spraying onto an adhesive substrate, or application of a coating composition UNITED STATES PATENTS comprising the intumescent agent. 3,535,130 10/1970 Webb 117/136 X 3,663,464 5/1972 Sawko..... 117/136 X 8 Claims, No Drawings 3,707,554 12/1972 Hardy 117/136 X OTHER PUBLICATIONS Northey, Sulfonamides, pps. 35-37, 9294 (1948) PROCESS FOR PROTECTING A SUBSTRATE WITH AN ARYLSULFONAMIDOTHIADIAZOLE OR OXADIAZOLE INTUMESCENT AGENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to intumescent compositions and more particularly relates to such compositions containing a one-component intumescent agent.

2. Description of the Prior Art It is known that a substrate may be protected from heat and fire by the application of an intumescent composition. lntumescent compositions of the prior art usually contain an intumescent agent having at least three components; i.e., a carbonific, a spumific, and a catalyst; and they are typically characterized by the disadvantages of high cost, low spreading rate, relatively poor efficiency, poor water resistance, and poor weatherability.

As disclosed in US. Pat. No. 3,535,130, it has already been discovered that a one-component intumescent agent has advantages over multicomponent intumescent agents. However, the intumescent agents of the patent have poor adherence to substrates and have an undesirable degree of moisture sensitivity.

SUMMARY OF THE INVENTION An object of this invention is to provide a novel class of one-component intumescent agents.

Another object is to provide such intumescent agents having good efficiency and a low level of moisture sensitivity.

These and other objects are attained by using as intumescent agents compounds corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon, halohydrocarbon, or acyl, and R" is a thiadiazolyl, substituted thiadiazolyl, oxadiazolyl, or substituted oxadiazolyl radical.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intumescent agents of the invention may be any compounds corresponding to the above formula. However, they are preferably compounds wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof. When the aromatic ring bears organic substituents, it is usually preferred that these substituents contain one to five carbon atoms. When there are halo substituents, it is usually preferred that they be chloro or bromo. It is also preferred that the aromatic ring have at least one free reactive position.

As indicated above, R of the formula may be hydrogen or a hydrocarbon, halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, or bromoalkyl radical containing one to five carbon atoms, a phenyl, chlorophenyl, or bromophenyl radical, or an aliphatic or aromatic acyl radical.

R" is preferably a thiadiazolyl or oxadiazolyl radical, but it may be substituted if desired. The substituted thiadiazolyl and oxadiazolyl radicals most commonly found in these compounds are the chloro, bromo, carboxy, hydroxy, amino, thio, sulfonamido, C -C alkyl, C -C alkoxy, and phenyl derivatives, but compounds containing other substituted thiadiazolyl and oxadiazolyl radicals are also utilizable. When R" is a substituted thiadiazolyl or oxadiazolyl radical, the nitrogen of the sulfonamide group may be attached directly to the thiadiazole or oxadiazole ring, or it may be attached to the ring through the substituent.

Exemplary of the intumescent agents of the invention are 5-sulfanilamido-1,2,3-thiadiazole, 3-sulfanilamido- 2-sulfanilamido-l ,3 ,4-thiadiazole,

2-(4-amino-3- 2-(2- l,2,4-thiadiazole, 3-sulfanilamidol ,2,5-thiadiazole, chlorobenzenesulfonamido)-1,3,4-thiadiazole, amino-4-bromobenzenesulfonamido)-1,3 ,4- thiadiazole, 3-(4-amino-2-ethylbenzenesulfonamido)- l,2,4-thiadiazole, 5-( 3-amino-4-chloromethylbenzenesulfonamido)-1 ,2,3-thiadiazole, 3-(4-amino-2- butoxybenzenesulfonamido)-l,2,5-thiadiazole, 2-(4- amino-3-chloromethyoxybenzenesulfonamido )-l ,3,4- thiadiazole, 2-(4-amino-3-hydroxybenzenesulfonamido)-l,3,4-thiadiazole, 2-(4-amino-3-carboxybenzenesulfonamido )-1 ,3 ,4-thiadiazole, 2-( 3 ,4- diaminobenzenesulfonamido)-l,3,4-thiadiazole, 2-(4- amino-2-acetamidobenzenesulfonamido )-l ,3 ,4- thiadiazole, 2-(2-amino-4-nitrobenzenesulfonamido)- 1,3 ,4-thiadiazole, 2-(4-methylaminobenzenesulfonamido)-l ,3 ,4-thiadiazole, 2-( 4- chloroethylaminobenzenesulfonamido)-l ,3,4- thiadiazole, 2-(4-bromomethylaminobenzenesulfonamido)-l ,3,4-thiadiazole, 2-(4-phenylaminobenzenesulfonamido l ,3 ,4-thiadiazole, 2-[ 4-( pchlorophenylamino )benzenesulfonamido1-l ,3 ,4- thiadiazole, 2-[4-(p-bromophenylamino)benzenesulfonamido]-l ,3 ,4-thiadiazole, 2-(p-acetamidobenzenesulfonamido)-l ,3 ,4-thiadiazole, 3-( pbenzamidobenzenesulfonamido)-l,2,4-thiadiazole, 5- chloro-2-sulfanilamido-l,3,4-thiadiazole, 5-bromo-3- sulfanilamido-l ,2,4-thiadiazole, S-ethylcarboxy- 2-sulfanilamido-l ,3 ,4-thiadiazole, 4-hydroxy-3- sulfanilamido-l ,2,5-thiadiazole, 2-sulfanilamidoamino- 1,3,4-thiadiazole, 2-amino-5-sulfanilamido-l ,3 ,4- thiadiazole, 5-methylthio-Z-sulfanilamido-1 ,3 ,4- thiadiazole, 2,5-disulfanilamido-l,3,4-thiadiazole, 5-

methyl-2-sulfanilamido-l ,3 ,4-thiadiaz0le, 5-ethyl-2- sulfanilamido-l ,3,4-thiadiazole, S-methyl- 3sulfanilamido-l ,2,4-thiadiazole, 5-ethoxy-3- sulfanilamido-l ,2,4-thiadiazole, 4-phenyl-3- sulfanilamido-l ,2,5-thiadiazole, 5-phenyl-2- sulfanilamido-1,3 ,4-thiadiazole, the corresponding napththalene compounds, the corresponding derivatives of oxathiazole, etc. When not readily available, these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescent agents of the invention may be applied in any suitable manner, e.g., electrodeposition, spraying of powdered intumescent agent onto an adhesive substrate, etc. However, it is usually preferred to compound the intumescent agent with a binder, e.g., nitrocellulose, and optionally also with one or more of the other ingredients conventionally used in intumescent compositions, e.g., stabilizers, dispersing agents, pigments, driers, biocides, anti-foamers, thickeners, protective colloids, fillers, blowing agents, etc.; disperse the composition in a suitable liquid medium, e.g., water or a solvent or solvent mixture; and apply the coating composition thus formed to the substrate to be protected. As is the case with conventional intumescent coating compositions, it is frequently convenient to apply these coating compositions in the form of a paint having a solids content of about -70 percent by weight and an intumescent agent/binder weight ratio of about 0.075-14/1 to deposit a coating having a dry thickness of about 0.001-0.75 inch.

The intumescent agents of the invention are efficient, have low moisture sensitivity, and intumesce to form foams having good volume, cell structure, and adherence to substrates, such as wood, metal, and plastics. They are also useful as flame retardants in normally flammable compositions.

The following example is given to illustrate the invention and is not intended as a limitation thereof.

EXAMPLE I sulfanilamido-l ,3 ,4-thiadiazole, 5-ethyl-2- sulfanilamido-l ,3 ,4-thiadiazole, 5-methyl-3- sulfanilamido-l ,2,4-oxadiazole, 4-phenyl-3- sulfanilamido-l ,2,5-oxadiazole, and the other intumescent agents mentioned in the specification are substituted for the intumescent agents of the Example.

It is obvious that many variations may be made in the products and processes set forth above without departing from the spirit and scope of this invention.

What is claimed is:

1. A process for protecting a substrate from heat and fire which comprises applying thereto an intumescent comosition comprising as the intumescent agent a compound corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon, halohydrocarbon, or acyl, and R" is a thiadiazolyl, substituted thiadiazolyl, oxadiazolyl, or substituted oxadiazolyl radical.

2. The process of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.

3. The process of claim 1 wherein R" is a thiadiazolyl or oxadiazolyl radical or an amino, sulfonamido, thio, alkyl, or phenyl derivative thereof.

4. The process of claim 1 wherein the intumescent agent is 2-sulfanilamido-1,3,4-thiadiazole.

5. The process of claim 1 wherein the intumescent agent is 5-methyl-2-sulfanilamido-l ,3,4-thiadiaz0le.

6. The process of claim 11 wherein the intumescent agent is 5ethyl-2-sulfanilamido-l ,3,4-thiadiazole.

7. The process of claim Il wherein the intumescent agent is 5-methyl-3-sulfanilamido-l,2,4-oxadiazole.

8. The process of claim 1 wherein the intumescent agent is 4-phenyl-3-sulfanilamido-1,2,5-oxadiaz0le. 

2. The process of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.
 3. The process of claim 1 wherein R'''' is a thiadiazolyl or oxadiazolyl radical or an amino, sulfonamido, thio, alkyl, or phenyl derivative thereof.
 4. The process of claim 1 wherein the intumescent agent is 2-sulfanilamido-1,3,4-thiadiazole.
 5. The process of claim 1 wherein the intumescent agent is 5-methyl-2-sulfanilamido-1,3,4-thiadiazole.
 6. The process of claim 1 wherein the intumescent agent is 5-ethyl-2-sulfanilamido-1,3,4-thiadiazole.
 7. The process of claim 1 wherein the intumescent agent is 5-methyl-3-sulfanilamido-1,2,4-oxadiazole.
 8. The process of claim 1 wherein the intumescent agent is 4-phenyl-3-sulfanilamido-1,2,5-oxadiazole. 